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electric drive for a tunnel stern?

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  • pkj49cello
    I am planning to build a boat for the rivers and marshes of the coastal Carolinas. I like the idea of the tunnel stern for its shallow draft, protection of the
    Message 1 of 15 , Feb 15, 2007
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      I am planning to build a boat for the rivers and marshes of the
      coastal Carolinas.
      I like the idea of the tunnel stern for its shallow draft, protection
      of the propeller etc, but how would this kind of hull take to a
      totally displacement mode? Would it be efficient enough for the low
      power put out by most electric systems?
      I have read most of the old threads on tunnel sterns, but all of those
      assumed a full power motor. Am I crazy?

      Doug
    • Kenneth Grome
      Hi Doug, Most sailboats are displacement boats, so you might do better by using your electric motor in a sailboat and foregoing the sails. There are lots of
      Message 2 of 15 , Feb 16, 2007
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        Hi Doug,

        Most sailboats are displacement boats, so you might do better by using your electric motor in a sailboat and foregoing the sails. There are lots of shallow water sailboats available these days. Jim Michalak has some shallow water boats you might want to consider:

        http://www.duckworksbbs.com/plans/jim/michalak.htm

        All the Atkin tunnel hulls I'm familiar with are planing boats that require more power than most electrics can put out. Don't forget, it takes a lot of energy to suck that water up into the tunnel so these boats can function properly in shallow water, and anything that sucks energy out of your batteries is not going to be good for long running times.

        Sincerely,
        Kenneth Grome
        Bagacay Boatworks
        www.bagacayboatworks.com





        > I am planning to build a boat for the rivers and marshes of the
        > coastal Carolinas.
        > I like the idea of the tunnel stern for its shallow draft, protection
        > of the propeller etc, but how would this kind of hull take to a
        > totally displacement mode? Would it be efficient enough for the low
        > power put out by most electric systems?
        > I have read most of the old threads on tunnel sterns, but all of those
        > assumed a full power motor. Am I crazy?
        >
        > Doug

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      • Sal's Dad
        Look at Twinkle http://www.boat-links.com/Atkinco/Utilities/Twinkle.html. 3 h.p. will be ample for speeds up to six miles an hour. You might be able to build
        Message 3 of 15 , Feb 16, 2007
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          Look at Twinkle http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
          "3 h.p. will be ample for speeds up to six miles an hour."

          You might be able to build this boat light, or (God forbid!) modify the plans, to reduce draft to less than the 9" estimated. In any event, a small tunnel like this would probably be better for low-power.

          Or, something like Sergeant Faunce http://www.boat-links.com/Atkinco/Utilities/SergeantFaunce.html - a long, lean 8HP beauty.

          Sal's Dad


          [Non-text portions of this message have been removed]
        • Ken Grome
          Good recommendation Sal s Dad, I had forgotten all about Twinkle! I still don t think a tunnel hull is the ideal design for an electric motor because it takes
          Message 4 of 15 , Feb 16, 2007
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            Good recommendation Sal's Dad, I had forgotten all about Twinkle!

            I still don't think a tunnel hull is the ideal design for an electric motor
            because it takes a lot of power to lift the water into the tunnel. Gas
            engines can easily produce this much power but electrics would probably drain
            batteries fast in this effort.

            Then again for short distances an electric motor in a tunnel hull like Twinkle
            might be just the thing, although I agree that this boat can probably be
            built lighter and still be safe and plenty strong enough for its intended use
            -- and lighter is often better when limited power is available.

            Sincerely,
            Kenneth Grome
            Bagacay Boatworks
            www.bagacayboatworks.com








            On Friday 16 February 2007 19:53, Sal's Dad wrote:
            > Look at Twinkle http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
            > "3 h.p. will be ample for speeds up to six miles an hour."
          • derbyrm
            If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications; but not worth the effort
            Message 5 of 15 , Feb 16, 2007
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              If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications; but not worth the effort for the sort of steady state effort that most boat propulsion systems are used in.

              Every time you convert from one form of energy to a different form, you lose a significant percentage to heating the atmosphere.
              chemical => mechanical -- direct connection of gas engine to prop
              vs
              chemical => electrical => mechanical -- battery to motor to prop
              vs
              chemical => mechanical => electrical => mechanical -- driving electric motor with genset

              Roger
              derbyrm@...
              http://home.insightbb.com/~derbyrm

              ----- Original Message -----
              From: Ken Grome
              To: AtkinBoats@yahoogroups.com
              Sent: Friday, February 16, 2007 10:33 AM
              Subject: Re: [AtkinBoats] Re:electric drive for a tunnel stern?


              Good recommendation Sal's Dad, I had forgotten all about Twinkle!

              I still don't think a tunnel hull is the ideal design for an electric motor
              because it takes a lot of power to lift the water into the tunnel. Gas
              engines can easily produce this much power but electrics would probably drain
              batteries fast in this effort.

              Then again for short distances an electric motor in a tunnel hull like Twinkle
              might be just the thing, although I agree that this boat can probably be
              built lighter and still be safe and plenty strong enough for its intended use
              -- and lighter is often better when limited power is available.

              Sincerely,
              Kenneth Grome
              Bagacay Boatworks
              www.bagacayboatworks.com

              On Friday 16 February 2007 19:53, Sal's Dad wrote:
              > Look at Twinkle http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
              > "3 h.p. will be ample for speeds up to six miles an hour."





              [Non-text portions of this message have been removed]
            • Bruce C. Dillahunty
              ... I certainly see your point, but... The River Belle (35 tunnel hull) was spec ed to have 80hp and run 15mph... this would be above hull speed (planing)...
              Message 6 of 15 , Feb 16, 2007
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                Ken Grome wrote:
                > I still don't think a tunnel hull is the ideal design for an electric motor
                > because it takes a lot of power to lift the water into the tunnel. Gas
                > engines can easily produce this much power but electrics would probably drain
                > batteries fast in this effort.
                >
                > Then again for short distances an electric motor in a tunnel hull like Twinkle
                > might be just the thing, although I agree that this boat can probably be
                > built lighter and still be safe and plenty strong enough for its intended use
                > -- and lighter is often better when limited power is available.
                >
                I certainly see your point, but... The River Belle (35' tunnel hull) was
                spec'ed to have 80hp and run 15mph... this would be above hull speed
                (planing)... for the size boat and speed, that's low power (isn't it???)
                compared to many of today's boats.

                If they were efficient (good speed at low hp) with gas/diesel then they
                should still be efficient with electric, I would think... just thinking,
                here :-)

                Anybody know how they do at displacement speeds?

                Other than the tunnel, it seems like a similar hull to the Mundoo series
                (http://www.duckflatwoodenboats.com/mainpages/mundoo.php) which have
                been doing well with electric... guess it all comes down to the tunnel
                effect.

                Bruce

                --
                Bruce Dillahunty
                bdillahu@...
                http://www.craftacraft.com
              • Lewis E. Gordon
                Twinkle is a nice design, but don t forget the weight of the batteries you need to carry along. At 16 feet and flat bottomed it might be difficult to get the
                Message 7 of 15 , Feb 16, 2007
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                  Twinkle is a nice design, but don't forget the weight of the batteries
                  you need to carry along. At 16 feet and flat bottomed it might be
                  difficult to get the batteries low enough to get be ultra "seaworthy".
                  Also at 16 feet, MotoSkiff, being V-bottomed might be a better choice.
                  While not a tunnel stern design, the draft is a modest 11 inches and
                  the propeller is well protected. And, she was designed for low power
                  and to be easily built.

                  There is also Sixteen Too and Heron (tunnel sterned) at 17 feet and
                  not as easy to build. I used to boat off Brunswick County, NC and also
                  up in the Beaufort (NC) area. I can just imagine cruising along with
                  quiet electric power in MotoSkiff up the Lockwood Folly river and
                  seeing the alligators sunning and watching the ospreys fishing. It was
                  a very special area in the coastal Carolinas.

                  Lewis,

                  --- In AtkinBoats@yahoogroups.com, Ken Grome <bagacayboatworks@...> wrote:
                  >
                  > Good recommendation Sal's Dad, I had forgotten all about Twinkle!
                  >
                  > I still don't think a tunnel hull is the ideal design for an
                  electric motor
                  > because it takes a lot of power to lift the water into the tunnel. Gas
                  > engines can easily produce this much power but electrics would
                  probably drain
                  > batteries fast in this effort.
                  >
                  > Then again for short distances an electric motor in a tunnel hull
                  like Twinkle
                  > might be just the thing, although I agree that this boat can
                  probably be
                  > built lighter and still be safe and plenty strong enough for its
                  intended use
                  > -- and lighter is often better when limited power is available.
                  >
                  > Sincerely,
                  > Kenneth Grome
                  > Bagacay Boatworks
                  > www.bagacayboatworks.com
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  > On Friday 16 February 2007 19:53, Sal's Dad wrote:
                  > > Look at Twinkle
                  http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
                  > > "3 h.p. will be ample for speeds up to six miles an hour."
                  >
                • pkj49cello
                  ... Gas ... Many thanks for your thoughts. I see Kenneth s point about tunnel sterns requiring more power than an electric motor would want to provide. Maybe
                  Message 8 of 15 , Feb 16, 2007
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                    --- In AtkinBoats@yahoogroups.com, "Lewis E. Gordon"
                    <l_gordon_nica@...> wrote:
                    >
                    > Twinkle is a nice design, but don't forget the weight of the batteries
                    > you need to carry along. At 16 feet and flat bottomed it might be
                    > difficult to get the batteries low enough to get be ultra "seaworthy".
                    > Also at 16 feet, MotoSkiff, being V-bottomed might be a better choice.
                    > While not a tunnel stern design, the draft is a modest 11 inches and
                    > the propeller is well protected. And, she was designed for low power
                    > and to be easily built.
                    >
                    > There is also Sixteen Too and Heron (tunnel sterned) at 17 feet and
                    > not as easy to build. I used to boat off Brunswick County, NC and also
                    > up in the Beaufort (NC) area. I can just imagine cruising along with
                    > quiet electric power in MotoSkiff up the Lockwood Folly river and
                    > seeing the alligators sunning and watching the ospreys fishing. It was
                    > a very special area in the coastal Carolinas.
                    >
                    > Lewis,
                    >
                    > --- In AtkinBoats@yahoogroups.com, Ken Grome <bagacayboatworks@> wrote:
                    > >
                    > > Good recommendation Sal's Dad, I had forgotten all about Twinkle!
                    > >
                    > > I still don't think a tunnel hull is the ideal design for an
                    > electric motor
                    > > because it takes a lot of power to lift the water into the tunnel.
                    Gas
                    > > engines can easily produce this much power but electrics would
                    > probably drain
                    > > batteries fast in this effort.
                    > >
                    > > Then again for short distances an electric motor in a tunnel hull
                    > like Twinkle
                    > > might be just the thing, although I agree that this boat can
                    > probably be
                    > > built lighter and still be safe and plenty strong enough for its
                    > intended use
                    > > -- and lighter is often better when limited power is available.
                    > >
                    > > Sincerely,
                    > > Kenneth Grome
                    > > Bagacay Boatworks
                    > > www.bagacayboatworks.com
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > > On Friday 16 February 2007 19:53, Sal's Dad wrote:
                    > > > Look at Twinkle
                    > http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
                    > > > "3 h.p. will be ample for speeds up to six miles an hour."
                    > >
                    >



                    Many thanks for your thoughts. I see Kenneth's point about tunnel
                    sterns requiring more power than an electric motor would want to
                    provide. Maybe my yen for a tunnel stern boat will have to wait till
                    this present itch is scratched.

                    May I give you all some more of my design wishes? Please bear with me
                    and change channels if you need to.

                    I spent three weeks in the ACE basin of coastal SC last spring. This
                    is an area of marshes and creeks between Savannah GA and Charleston
                    SC. It is mostly undeveloped, being protected by various Wildlife
                    Management areas. It has strong tidal currents, some stretches of open
                    water, but is mostly protected. The roughest conditions I encountered
                    were in Charleston harbour, shortly after launching.
                    The whole area is incredible for wildlife. One anchorage off the
                    Edisto river, I had (at different times) alligators and dolphins
                    swimming close to the boat.
                    I was on my 23 ft trailer sailor, but due to the narrow channels,
                    contrary winds and a boat (bless her heart), that doesn't tack worth a
                    hoot, we spent 100% of time listening to the two stroke.

                    So what I think I need, is a 25 foot, easilly driven, room for two,
                    electric powered boat. I see using solar panels to power the batteries
                    for short hops, and a generator to help out for the longer runs.
                    Shallow draft would allow easy launches and access to distant creeks,
                    while a flat bottom would allow me to dry out should I want to really
                    explore. That is where the tunnel stern thought came from.

                    I share Lewis's dream of silently cruising past all kinds of salty
                    wildlife- really I suppose, sailing without the sails.

                    Any thoughts?

                    Doug
                  • Bruce C. Dillahunty
                    ... I ll agree with that... I drive a Prius :-) ... I agree up to a point... there are a couple of mitigating factors though. 1) You can operate the mechanical
                    Message 9 of 15 , Feb 16, 2007
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                      derbyrm wrote:
                      > If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications;
                      I'll agree with that... I drive a Prius :-)
                      > but not worth the effort for the sort of steady state effort that most boat propulsion systems are used in.
                      >
                      > Every time you convert from one form of energy to a different form, you lose a significant percentage to heating the atmosphere.
                      > chemical => mechanical -- direct connection of gas engine to prop
                      > vs
                      > chemical => electrical => mechanical -- battery to motor to prop
                      > vs
                      > chemical => mechanical => electrical => mechanical -- driving electric motor with genset
                      >
                      I agree up to a point... there are a couple of mitigating factors though.

                      1) You can operate the mechanical (gas/whatever) at its optimum
                      efficiency instead of varying it to achieve other performance. This
                      probably wouldn't outweight the inefficiencies, but would help offset
                      them somewhat.

                      2) You can use other energy sources (solar/wind/etc.) to supplement the
                      gas... this is where the win is/is going to be in my opinion. I think in
                      a few years we'll keep seeing solar drop in price and rise in
                      effeciency. As I can get more power from the sun, I can rely on that gas
                      engine less.

                      Either way, its a neat technology :-)

                      Bruce
                      > Roger
                      > derbyrm@...
                      > http://home.insightbb.com/~derbyrm
                      >
                      >


                      --
                      Bruce Dillahunty
                      bdillahu@...
                      http://www.craftacraft.com
                    • sals_dad
                      First, check out the Yahoo Electricboats forum. Lots of intelligent discussion of electric propulsion. It has come a long way, but the limiting factor is
                      Message 10 of 15 , Feb 17, 2007
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                        First, check out the Yahoo Electricboats forum. Lots of intelligent
                        discussion of electric propulsion. It has come a long way, but the
                        limiting factor is still the very low capacity of lead-acid batteries
                        (compared with, say, a gallon of gasoline)

                        But for auxiliarry propulsion of a small sailboat, it might be just
                        the thing.

                        If I were you (and in fact I AM you - with a 21' sharpie that can't
                        beat worth a d*&^, beautiful quiet shallow waters with strong
                        currents...) I would (did) spend $300 at WalMart on a biggish Minn-
                        Kota trolling motor and a couple biggish batteries, and start messing
                        around. Add solar, generator, bigger batteries, etc as you think you
                        need them.

                        If you find the propulsion system meets your needs but your sailboat
                        doesn't, THEN think about a new hull.

                        Efficiency of electric? - as of today, it would be very difficult to
                        assemble an electric system as efficient as you can get with gasoline -
                        whether you measure efficiency in miles/dollar, miles/lb of
                        mechanical and fuel carried, miles/lb carbon burnt, whatever - unless
                        you can find a sweet spot of low usage, and high solar/wind charging.
                        The big advantage of electric in boats is the quiet...

                        Sal's Dad


                        > I was on my 23 ft trailer sailor, but due to the narrow channels,
                        > contrary winds and a boat (bless her heart), that doesn't tack worth
                        a
                        > hoot, we spent 100% of time listening to the two stroke.
                        >
                        > So what I think I need, is a 25 foot, easilly driven, room for two,
                        > electric powered boat....
                      • derbyrm
                        Many years ago, the editor of Analog Science Fact & Fiction, mused on the several forms of efficiency: - miles per gallon - miles per dollar - watts per pound
                        Message 11 of 15 , Feb 17, 2007
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                          Many years ago, the editor of Analog Science Fact & Fiction, mused on the several forms of efficiency:

                          - miles per gallon
                          - miles per dollar
                          - watts per pound
                          - watts per cubic foot
                          - watts per milligram of pollutants emitted at point of use
                          - watt-seconds per dollar of maintenance costs

                          People have suggested that we should use hydrogen fusion for power, like the sun does, but the sun's efficiency is something like one horsepower per cubic mile. (It's been a long time since I saw the actual figure.) Parking/docking such a vehicle would be difficult.

                          When we select a power system we unconsciously make a lot of choices on prejudice and then argue over some quantifiable thing like mpg. Sure, electric power is clean at point of use, but the total emissions for the system may be lousy; e.g. did the battery get charged by an old coal burning power plant? How long before the wind farms or solar cell arrays make a noticeable change in the weather? Land is about $10,000 per acre here in Southern Indiana, but up in the Chicago area, that money would buy only a few square feet. Electricity cost is primarily transmission cost, so don't talk about the square miles of desert out west.

                          I once spent several hobby years designing a modern steam car. Burns anything, as clean as you want to make it, full torque at zero rpm, quiet, and the Stanley Brothers built the best. (It failed for psychological and marketing reasons, not because it was bad technology.) An acquaintance pointed out that I'd never get my prototype to the level of comfort and convenience that a modern gas powered automobile offered, even with a superior power plant.

                          'tis a conundrum.

                          Roger (too old to start cutting metal now -- I've a boat to build)
                          derbyrm@...
                          http://home.insightbb.com/~derbyrm

                          ----- Original Message -----
                          From: Bruce C. Dillahunty
                          To: AtkinBoats@yahoogroups.com
                          Sent: Friday, February 16, 2007 10:07 PM
                          Subject: Re: [AtkinBoats] Re:electric drive for a tunnel stern?


                          derbyrm wrote:
                          > If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications;
                          I'll agree with that... I drive a Prius :-)
                          > but not worth the effort for the sort of steady state effort that most boat propulsion systems are used in.
                          >
                          > Every time you convert from one form of energy to a different form, you lose a significant percentage to heating the atmosphere.
                          > chemical => mechanical -- direct connection of gas engine to prop
                          > vs
                          > chemical => electrical => mechanical -- battery to motor to prop
                          > vs
                          > chemical => mechanical => electrical => mechanical -- driving electric motor with genset
                          >
                          I agree up to a point... there are a couple of mitigating factors though.

                          1) You can operate the mechanical (gas/whatever) at its optimum
                          efficiency instead of varying it to achieve other performance. This
                          probably wouldn't outweight the inefficiencies, but would help offset
                          them somewhat.

                          2) You can use other energy sources (solar/wind/etc.) to supplement the
                          gas... this is where the win is/is going to be in my opinion. I think in
                          a few years we'll keep seeing solar drop in price and rise in
                          effeciency. As I can get more power from the sun, I can rely on that gas
                          engine less.

                          Either way, its a neat technology :-)

                          Bruce
                          > Roger
                          > derbyrm@...
                          > http://home.insightbb.com/~derbyrm
                          >
                          >

                          --
                          Bruce Dillahunty
                          bdillahu@...
                          http://www.craftacraft.com





                          [Non-text portions of this message have been removed]
                        • donschultz8275
                          ... batteries ... You could build a Jim Michalak AF4G. 22 flattie skiff with a slot type slot type tunnel at lease 6x1 in proportion ahead of the transom.
                          Message 12 of 15 , Feb 17, 2007
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                            --- In AtkinBoats@yahoogroups.com, "pkj49cello" <Johnst1@...> wrote:
                            >
                            > So what I think I need, is a 25 foot, easilly driven, room for two,
                            > electric powered boat. I see using solar panels to power the
                            batteries
                            > for short hops, and a generator to help out for the longer runs.
                            > Shallow draft would allow easy launches and access to distant creeks,
                            > while a flat bottom would allow me to dry out should I want to really
                            > explore. That is where the tunnel stern thought came from.
                            >
                            > I share Lewis's dream of silently cruising past all kinds of salty
                            > wildlife- really I suppose, sailing without the sails.
                            >
                            > Any thoughts?
                            >
                            > Doug
                            >

                            You could build a Jim Michalak AF4G. 22' flattie skiff with a slot
                            type slot type tunnel at lease 6x1 in proportion ahead of the
                            transom. The motor well could hold the generator and gasoline, but
                            I'd put the batteries amidship.

                            http://www.duckworksbbs.com/plans/jim/af4/grande/index.htm

                            Michalak's Twister is another possibility but is only a 16'
                            motorsailor.

                            http://www.duckworksbbs.com/plans/jim/twister/index.htm

                            Checkout the simple tunnel design for this shallow water fishing
                            boat. This is what I suggest could be added to the AF4G.

                            http://www.bateau.com/proddetail.php?prod=XF20

                            Click the link then click on the 'study plan' link. Part way down
                            there is an excellent color drawing of the "tunnel"

                            Don Schultz
                          • Ken Grome
                            Hi Doug, Canoes and kayaks are so slim that they slice very easily through the water. Some of them can run all day on trolling motors before their batteries
                            Message 13 of 15 , Feb 17, 2007
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                              Hi Doug,

                              Canoes and kayaks are so slim that they slice very easily through the water.
                              Some of them can run all day on trolling motors before their batteries give
                              out. Maybe canoes or kayaks are what you really need for the type
                              of "exploration boating" you've described ...

                              Have you ever thought of using two boats? I like the ones shown in the links
                              below . How about building two of them so each of you can have your own
                              boat:

                              http://www.jemwatercraft.com/proddetail.php?prod=Muskoka
                              http://jemwatercraft.com/proddetail.php?prod=BucXW

                              These boats can handle 800+ pounds of people and gear each, for a total
                              capacity of more than 1600 pounds. That's a lot for two people! If it's too
                              much capacity you could always build two of this model for a total capacity
                              of 1000 pounds:

                              http://jemwatercraft.com/proddetail.php?prod=Buccaneer

                              You could put an electric trolling motor on any of these boats.

                              If I were doing your exploring I might put a trolling motor on each boat, then
                              bring along a very small (and quiet) 4-stroke outboard. Just put the
                              outboard on the front boat and tow the other boat on your long treks.

                              If you get an outboard with a charging circuit it would even recharge your
                              batteries for you!

                              Sincerely,
                              Kenneth Grome
                              Bagacay Boatworks
                              www.bagacayboatworks.com






                              > I spent three weeks in the ACE basin of coastal SC last spring. This
                              > is an area of marshes and creeks between Savannah GA and Charleston
                              > SC. It is mostly undeveloped, being protected by various Wildlife
                              > Management areas. It has strong tidal currents, some stretches of open
                              > water, but is mostly protected. The roughest conditions I encountered
                              > were in Charleston harbour, shortly after launching.
                              > The whole area is incredible for wildlife. One anchorage off the
                              > Edisto river, I had (at different times) alligators and dolphins
                              > swimming close to the boat.
                              > I was on my 23 ft trailer sailor, but due to the narrow channels,
                              > contrary winds and a boat (bless her heart), that doesn't tack worth a
                              > hoot, we spent 100% of time listening to the two stroke.
                              >
                              > So what I think I need, is a 25 foot, easilly driven, room for two,
                              > electric powered boat. I see using solar panels to power the batteries
                              > for short hops, and a generator to help out for the longer runs.
                              > Shallow draft would allow easy launches and access to distant creeks,
                              > while a flat bottom would allow me to dry out should I want to really
                              > explore. That is where the tunnel stern thought came from.
                              >
                              > I share Lewis's dream of silently cruising past all kinds of salty
                              > wildlife- really I suppose, sailing without the sails.
                              >
                              > Any thoughts?
                              >
                              > Doug
                            • Chris Partridge
                              ... anything, as clean as you want to make it, full torque at zero rpm, quiet, and the Stanley Brothers built the best. (It failed for psychological and
                              Message 14 of 15 , Feb 18, 2007
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                                >>>I once spent several hobby years designing a modern steam car. Burns
                                anything, as clean as you want to make it, full torque at zero rpm, quiet,
                                and the Stanley Brothers built the best. (It failed for psychological and
                                marketing reasons, not because it was bad technology.) An acquaintance
                                pointed out that I'd never get my prototype to the level of comfort and
                                convenience that a modern gas powered automobile offered, even with a
                                superior power plant.





                                The advantages you list, especially full torque at zero rpm, are just what
                                you need in a boat. How about designing a marine version?

                                Chris



                                [Non-text portions of this message have been removed]
                              • derbyrm
                                Actually, the marine application is quite different; little starting and stopping, relatively limited environmental temperature changes, greater need for
                                Message 15 of 15 , Feb 18, 2007
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                                  Actually, the marine application is quite different; little starting and stopping, relatively limited environmental temperature changes, greater need for economy. Marine steam plants used quite exotic arrangements in the name of efficiency; compounding, feedwater heaters, economizers, ...

                                  Everything I know about Stanley Steamers came from a wonderful little book: "The Story of a Stanley Steamer" by George Woodbury. He restored a 1917(?) model from terribly decrepit condition but was able to talk to original owners and mechanics.

                                  Some gems I remember:

                                  One of his initial test drives after years of restoration found him cruising down a country road. He glanced down at the speedometer and discovered he was doing seventy miles an hour on the forty year old wooden spoked wheels. He slowed gently but immediately. (A Stanley built steamer held the world's speed record for a long time -- 114 mph on the sands of Daytona Beach with really primitive suspension.)

                                  His neighbors had a tennis court near his garage. One evening he came back from a ride, noticed the neighbor's wife about to serve, and, without thinking, tripped the boiler blow down valve. The serve went into the next county. (Railroad locomotives had mufflers on their blowdown valves to keep the neighbors happy.)

                                  His wife took the car to town one afternoon. Fires in the boiler compartment were not significant and went out promptly, but someone had called the fire department. If they were allowed to dowse it, she would be stuck for an hour or so while she got pressure back up, so she fled town, streaming fire and smoke, and pursued by the fire truck with sirens and bell.

                                  As I said, I'm too old to start cutting metal and ideas that look great on paper often turn out differently in practice.

                                  Roger
                                  derbyrm@...
                                  http://home.insightbb.com/~derbyrm

                                  ----- Original Message -----
                                  From: Chris Partridge
                                  To: AtkinBoats@yahoogroups.com
                                  Sent: Sunday, February 18, 2007 9:19 AM
                                  Subject: RE: [AtkinBoats] Re:electric drive for a tunnel stern?




                                  >>>I once spent several hobby years designing a modern steam car. Burns anything, as clean as you want to make it, full torque at zero rpm, quiet, and the Stanley Brothers built the best. (It failed for psychological and marketing reasons, not because it was bad technology.) An acquaintance pointed out that I'd never get my prototype to the level of comfort and convenience that a modern gas powered automobile offered, even with a superior power plant.

                                  The advantages you list, especially full torque at zero rpm, are just what you need in a boat. How about designing a marine version?

                                  Chris
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